1. Field of the Invention
This invention relates generally to spray booths. More specifically, it relates to the creation of airflow onto the surface of an object without the addition of external air into the spray booth.
2. Description of the Related Art
When painting a vehicle or other object, drying or curing times can limit the amount of throughput. One common way to spray a vehicle is by using a spray booth. These booths provide advantages such as reducing particulate, confining paint overspray and evaporated solvents, and reducing drying times. To accelerate drying, air is flowed through the booth and over the vehicle. For waterborne paints, water in the paint travels to the surface to evaporate. As the air flows over the surface of the paint, it tends to enhance evaporation of the water, thereby reducing drying times.
A wide variety of spray booths are in existence. Perhaps the most common types are downdraft and semi-vertical spray booths that use a housing positioned over an open floor grate or an exhaust outlet near the bottom of the walls. Air from the ceiling and any entrained paint overspray and solvents are drawn downward over the vehicle during spraying and drying and are then exhausted through the floor grate or exhaust opening.
An example of such spray booths are described in U.S. Pat. Nos. 6,533,654 and 7,045,013, incorporated herein by reference. Typical flow rates may be about 80 to 100 feet per minute over horizontal surfaces. Even at elevated temperatures and a down draft of semi-vertical draft, it can take up to 40 minutes for the entire vehicle to dry sufficiently to permit removal from the spray booth. Until the automobile is dry, it is usually maintained in the spray booth to prevent damage to the soft paint.
To reduce drying times, some have used heaters to increase the temperature within the booth. Others have tried to increase flow rates using nozzles. See, for example, U.S. Pat. No. 5,456,023, the complete disclosure of which is herein incorporated by reference. This invention is related to other techniques for reducing drying and curing times.
The prior art has also contemplated a plenum within the ceiling of the spray booth with filter media directly above a fan that blows air onto the top of the object in the spray booth. However, having filter media on the top side plenum directly above the fan hinders the maximum amount of air being filtered through the plenum, particularly if air is not directly added into the filter.
Accordingly, what is needed is an improved, more efficient spray booth that will reduce drying and curing times while drying more evenly over the entirety of the vehicle or other object. However, in view of the art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill how the art could be advanced.
While certain aspects of conventional technologies have been discussed to facilitate disclosure of the invention, Applicants in no way disclaim these technical aspects, and it is contemplated that the claimed invention may encompass one or more of the conventional technical aspects discussed herein.
The present invention may address one or more of the problems and deficiencies of the prior art discussed above. However, it is contemplated that the invention may prove useful in addressing other problems and deficiencies in a number of technical areas. Therefore, the claimed invention should not necessarily be construed as limited to addressing any of the particular problems or deficiencies discussed herein.
In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.